The Discover tab now houses a single stream of Tweets, Trends, and Activities, rather than segregated sections. A dedicated search button has been added to the top of the app next to the tweet button, allowing for easier searches, and the Connect tab has been improved.

Here's a full list of the changes:

Quote:

-Instantly access great content with improvements to search and Discover on iPhone.
-Discover delivers a single stream of Tweets, Trends, Activity and accounts to follow.
-Pull to refresh or keep scrolling to see more content.
-Search now shows the most relevant mix of people, Tweets and photos.
-It's also easier to use search with one button at the top of the app.
-You can see your five most recent searches and tap them to redo the search, or you can clear your recent search history.
-Links instantly open web pages when you tap URLs in your stream.
-Performance improvements make launch times faster, especially for older iOS devices.
-Connect shows interactions like new followers, retweets and mentions by default. You can switch to "view mentions only" in settings.
-Improved right-to-left language support for Arabic and Hebrew.
-Bug fixes and other improvements.

The newly updated Twitter app is currently available for download from the App Store. [Direct Link]